DOVER — Attorneys defending the Dover man suspected of killing University of New Hampshire student Elizabeth Marriott are reviewing hundreds of pages of police reports, witness interviews and other evidence collected in the murder case.

According to court documents, prosecutors have provided the defense team for 30-year-old Seth Mazzaglia with more than 1,200 pages of police reports. Other discovery materials produced in the case include laboratory reports and 12 disks containing audio recordings and other “digital data,” according to court documents filed last week.

Prosecutors have once again requested an extension to prepare their case against Mazzaglia. They were granted a similar extension in January. It bumped the deadline by which prosecutors must bring an indictment against Mazzaglia to the end of February. The state is now asking for that deadline to be extended into April.

In a motion filed Jan. 29 in Strafford County Superior Court, Assistant Attorney General Peter Hinckley requested the extension, and detailed some of the new developments in the case.

Those developments include the arrest of 19-year-old Portsmouth resident Kathryn “Kat” McDonough. McDonough is accused of lying to police about her whereabouts and interaction with Marriott on the night Marriott went missing. McDonough was engaged in a romantic relationship with Mazzaglia before Marriott's disappearance, prosecutors have confirmed.

Investigators have also conducted additional interviews, and an “attempt was made” to begin presenting the case against Mazzaglia to a grand jury, according to the state's motion. The document doesn't elaborate on whether a jury proceeding took place.

Reached by phone on Tuesday, Hinckley declined to provide any additional information about the grand jury proceedings referenced in the motion.

“Grand jury proceedings are sealed, secret proceedings, so I can't expand on it beyond what I put in the motion,” he said.

In a court document, Hinckley wrote that the state is requesting additional time to “complete certain investigative steps” and continue interviewing witnesses. The results of certain tests are also still pending, according to the state's motion. Prosecutors are also seeking the extension because they need additional time to assess what level of charges are appropriate to bring against Mazzaglia, according to the motion.

On Jan. 2, a superior court judge granted prosecutors until the end of February to present their case against Mazzaglia to a grand jury. A judge will now consider whether to grant a request to push the timeline for an indictment into April.

Mazzaglia's attorney, public defender Joachim Barth, could not be reached for comment Tuesday on the state's request.